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heat flux Apportionment to Heterogeneous Surfaces Using flux Footprint Analysis

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Advances in Atmospheric Sciences 2008年第1期25卷 107-116页

作者：彭谷亮蔡旭晖张宏升李爱国胡非 Monique Y.LECLERC Department of Environmental Sciences Peking University Department of Atmospheric Sciences Peking University State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Science Laboratory for Environmental Physics University of Georgia

heat flux data collected from the Baiyangdian Heterogeneous Field Experiment were analyzed using the footprint method. High resolution （25 m） Landsat-5 satellite imaging was used to determine the land cover as one of four surface types： farmland, lake, wetland, or village. Data from two observation sites in September 2005 were used. One site （Wangjiazhai） was characterized by highly heterogeneous surfaces in the central area of the Baiyangdian： lake/wetland. The other site （Xiongxian） was on land with more uniform surface cover. An improved Eulerian analytical flux footprint model was used to determine “source areas” of the heat fluxes measured at towers located at each site from surrounding landscapes of mixed surface types. In relative terms results show that wetland and lake areas generally contributed most to the observed heat flux at Wangjiazhai, while farmland contributed most at Xiongxian. Given the areal distribution of surface type contributions, calculations were made to obtain the magnitudes of the heat flux from lake, wetland and farmland to the total observed flux and apportioned contributions of each surface type to the sensible and latent heat fluxes. Results show that on average the sensible heat flux from wetland and farmland were comparable over the diurnal cycle, while the latent heat flux from farmland was somewhat larger by about 30-50 W m-2 during daytime. The latent and sensible fluxes from the lake source in daytime were about 50 W m-2 and 100 W m-2 less, respectively, than from wetland and farmland. The results are judged reasonable and serve to demonstrate the potential for flux apportionment over heterogeneous surfaces.

关键词： Eulerian analytical model flux footprint heat flux heterogeneous surface

heat flux Through Slag Film and Its Crystallization Behavior

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Journal of Iron and Steel Research International 2008年第4期15卷 7-11,20页

作者： TANG Ping XU Chu-shao WEN Guang-hua ZHAO Yan-hong QI Xin College of Materials Science and Engineering Chongqing University Chongqing 400044 China

An experimental apparatus for simulating copper mold is used to quantify the heat flux through the slag film and to obtain a solid slag for further determining its crystallization behavior. The result indicates that both the chemical composition of the mold powder and the cooling rate have an important influence on the heat flux through the slag film. With increasing the binary basicity, the heat flux of slag film decreases at first, reaches the minimum at the basicity of 1.4, and then increases, indicating that the maximum binary basicity is about 1.4 for selecting ＂mild cooling＂ mold powder. The heat transfer through the slag film can be specified in terms of the crystalline ratio and the thickness of the slag film. Recrystallization of the solid slag occurs and must be considered as an important factor that may influence the heat transfer through the solid slag layer.

关键词： continuous casting mold powder slag film heat flux crystallization

Closed-Form Solution for a Circular Nanohole with Surface Effects Under Uniform heat flux

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Acta Mechanica Solida Sinica 2024年第1期37卷 43-52页

作者： Jieyao Tang Jieyan Zhao Haibing Yang Cunfa Gao State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China School of Civil Engineering and Transportation South China University of TechnologyGuangzhou 510641China College of Mechanics and Materials Hohai UniversityNanjing 211100China

This paper investigates the steady-state thermoelastic problem of a circular nanohole embedded in an infinitely large elastic plane subjected to a uniform far-field heat flux.A lowly conductive surface model is used to account for the effects of surface phonon scattering,while the complete Gurtin–Murdoch model is utilized to characterize the effects of surface tension and surface *** closed-form solution to the temperature and stress field surrounding the hole is derived in the context of complex variable *** numerical examples are presented to analyze the influence of surface effects on thermal stress *** is shown that surface effects induce notable increases in normal and shear stresses around the ***,all three stress components(hoop,normal,and shear)in the vicinity of the hole exhibit substantial augmentation with increasing surface tension and surface *** particular,it is found that the presence of surface effects amplifies the variation in stress gradients and intensifies stress concentration around the hole.

关键词： Circular nanohole Surface effect Thermal stress heat flux

Double-null divertor configuration discharge and disruptive heat flux simulation using TSC on EAST

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Plasma Science and Technology 2018年第7期20卷 35-40页

作者： Bo SHI Jinhong YANG Cheng YANG Desheng CHENG Hui WANG Hui ZHANG Haifei DENG Junli QI Xianzu GONG Weihua WANG Institute of Plasma Physics Hefei Institutes of Physical SciencesChinese Academy of SciencesHefei 230031People＇s Republic of China Science Island Branch of Graduate School University of Science and Technology of ChinaHefei 230031People＇s Republic of China Institute of Applied Physics Army Officer AcademyHefei 230031People＇s Republic of China

The tokamak simulation code （TSC） is employed to simulate the complete evolution of a disruptive discharge in the experimental advanced superconducting tokamak. The multiplication factor of the anomalous transport coefficient was adjusted to model the major disruptive discharge with double-null divertor configuration based on shot 61 916. The real-time feed-back control system for the plasma displacement was employed. Modeling results of the evolution of the poloidal field coil currents, the plasma current, the major radius, the plasma configuration all show agreement with experimental measurements. Results from the simulation show that during disruption, heat flux about 8 MW m-2 flows to the upper divertor target plate and about 6 MW m-2 flows to the lower divertor target plate. Computations predict that different amounts of heat fluxes on the divertor target plate could result by adjusting the multiplication factor of the anomalous transport coefficient. This shows that TSC has high flexibility and predictability.

关键词： TSC EAST disruptive discharge heat flux

Characteristics of divertor heat flux distribution with an island divertor configuration on the J-TEXT tokamak

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Plasma Science and Technology 2024年第12期26卷 9-17页

作者： Yutong YANG Yunfeng LIANG Wei YAN Shuangbao SHU Jiankun HUA Song ZHOU Qinghu YANG Jinlong GUO Ziyang JIN Wei XIE the J-TEXT Team State Key Laboratory of Advanced Electromagnetic Technology International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma PhysicsSchool of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074People’s Republic of China Forschungszentrum Jülich GmbH Institut für Energie-und Klimaforschung-PlasmaphysikPartner of the Trilateral Euregio Cluster(TEC)Jülich 52425Germany School of Instrument Science and Opto-electronics Engineering Hefei University of TechnologyHefei 230009People’s Republic of China 不详

On J-TEXT,the temporal evolution of heat flux distribution on the high-field side(HFS)divertor plate has been measured by an infrared(IR)camera during the plasma operation with an island divertor *** experiments,the island divertor configuration is an edge magnetic island chain structure surrounded by stochastic layers,which can be induced by resonant magnetic perturbations(RMPs).The experimental results show that the heat flux distribution on the HFS target plate depends significantly on the edge magnetic ***,the impact of hydrogen fueling using supersonic molecular beam injection(SMBI)on the divertor heat flux distributions is studied on J-TEXT with an island divertor *** has been observed that power detachment can be achieved when the radiation front approaches the last closed flux surface(LCFS)after each SMBI *** result may provide a method of access for divertor detachment on a fusion device with a three-dimensional(3D)boundary magnetic structure.

关键词： infrared camera island divertor heat flux SMBI power detachment

Evidence of vapor shielding effect on heat flux loaded on flowing liquid lithium limiter in EAST

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Plasma Science and Technology 2022年第9期24卷 45-51页

作者： Chenglong LI Guizhong ZUO R MANIGI K TRITZ D ANDRUCZYK Bin ZHANG Ruirong LIANG D OLIVER Zhen SUN Wei XU Xiancai MENG Ming HUANG Zhongliang TANG Binfu GAO Ning YAN Jiansheng HU Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031People’s Republic of China University of Science and Technology of China Hefei 230026People’s Republic of China Princeton University Plasma Physics Laboratory Princeton Princeton NJ 08543United States of America Johns Hopkins University BaltimoreMD 21211United States of America Center for Plasma Material Interactions Department of NuclearPlasma and Radiological EngineeringUniversity of Illinois Urbana-ChampaignUrbana IL 61801United States of America Institute of Energy Hefei Comprehensive National Science CenterHefei 230026People’s Republic of China CAS Key Laboratory of Photovoltaic and Energy Conservation Materials Hefei 230031People’s Republic of China

A lithium(Li)vapour layer was formed around a flowing liquid Li limiter to shield against the plasma incident power and reduce limiter heat flux in the EAST *** results revealed that after a plasma operation of a few seconds,the layer became clear,which indicated a strong Li emission with a decrease in the limiter surface *** emission resulted in a dense vapour around the limiter,and Li ions moved along the magnetic fleld to form a green shielding layer on the *** plasma heat flux loaded on the limiter,measured by the probe installed on the limiter,was approximately 52%lower than that detected by a fast-reciprocating probe at the same radial position without the limiter in ***,approximately 42%of the parallel heat flux was dissipated directly with the enhanced Li radiation in the discharge with the liquid metal infused trenches(LIMIT)*** observation revealed that the Li vapour layer exhibited an excellent shielding effect to liquid Li on plasma heat flux,which is a possible beneflt of liquid-plasma-facing components in future fusion devices.

关键词： liquid Li limiter Li vapor shielding heat flux EAST

Mixed convection boundary layer flow past vertical flat plate in nanofluid: case of prescribed wall heat flux

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Applied Mathematics and Mechanics(English Edition) 2015年第8期36卷 1091-1104页

作者： R.TRIMBITAS T.GROSAN I.POP Department of Mathematics Babes-Bolyai University

An analysis is carried out to investigate the steady mixed convection bound- ary layer flow of a water based nanofluid past a vertical semi-infinite flat plate. Using an appropriate similarity transformation, the governing partial differential equations are transformed into the coupled, nonlinear ordinary （similar） differential equations, which are then solved numerically for the Prandtl number Pr = 6.2. The skin friction coeffi- cient, the local Nusselt number, and the velocity and temperature profiles are presented graphically and discussed. Effects of the solid volume fraction φ and the mixed convection parameter λ on the fluid flow and heat transfer characteristics are thoroughly examined. Different from an assisting flow, it is found that the solutions for an opposing flow are non-unique. In order to establish which solution branch is stable and physically realizable in practice, a stability analysis is performed.

关键词： Nanofluid boundary layer mixed convection heat flux dual solution

Effects of System Pressure and heat flux on Bubble Nucleation and Growth

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Chinese Journal of Mechanical Engineering 2015年第5期28卷 964-970页

作者： QIU Chao ZHANG Huichen Transportation Equipments and Ocean Engineering College Dalian Maritime University

Characteristics of bubble nucleation and growth are critical for its application. It is affected by several factors including viscosity, surface tension and temperature. However, the effect of pressure on bubble nucleation and growth has been underreported, although it processes significant effect on above characteristics. In this work, a micro copper electrode is etched on a slab covered with copper to produce bubble on the surface by current input. The nucleation time of bubble is measured under different heat flux and system pressures. The nucleation and growth processes are recorded with a high speed camera in order to discuss the effects of heat flux and system pressure on bubble characteristics. The experiment results indicate that the micro electrode with higher heat flux produces more thermal energy, which makes the time of bubble nucleation shorter and the speed of bubble growth faster. Higher system pressure causes the increase of the critical nucleation temperature and also baffles the bubble nucleation and growth. Bubble growth includes the stages of rapid growth and dynamic equilibrium, with the speed being from fast to slow. In the former part of rapid growth, heat flux plays a dominant role in bubble growth. While the effect of system pressure on bubble growth becomes significant in the latter part of rapid growth. Both the nucleation time and bubble growth agree well with the theoretical analysis. The obtained results help to accurately control bubble nucleation and growth required in different application.

关键词： bubble nucleation system pressure heat flux

Boundary layer flow and heat transfer of a Casson fluid past a symmetric porous wedge with surface heat flux

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Chinese Physics B 2014年第4期23卷 390-395页

作者： Swati Mukhopadhyay Iswar Chandra Mandal Department of Mathematics The University of Burdwan

The aim of this paper is to investigate numerically the boundary layer forced convection flow of a Casson fluid past a symmetric porous wedge. Similarity transformations are used to convert the governing partial differential equations into ordinary ones. With the help of the shooting method, the reduced equations are then solved numerically. Comparisons are made with the previously published results in some special cases and they are found to be in excellent agreement with each other. The results obtained in this study are illustrated graphically and discussed in detail. The velocity is found to increase with an increasing Falkner-Skan exponent whereas the temperature decreases. With the rise of the Casson fluid parameter, the fluid velocity increases but the temperature is found to decrease in this case. Fluid velocity is suppressed with the increase of suction. The skin friction decreases with the increasing value of Casson fluid parameter. It is found that the temperature decreases as the Prandtl number increases and thermal boundary layer thickness decreases with the increasing value of Prandtl number. A significant finding of this investigation is that flow separation can be controlled by increasing the value of the Casson fluid parameter as well as by increasing the amount of suction.

关键词： symmetric wedge Casson fluid heat flux suction/blowing